The use of insect pheromones to control specifically targeted pest populations has gained increasing popularity as a viable, safe, and environmentally-friendly alternative to broad spectrum insecticides. To date, the environmental protection agency (EPA) has approved approximately twenty female sex pheromones of the lepidopteran order of insects as active ingredients for pest control. A major factor hindering more widespread use of pheromones for pest control is the production cost of synthetic pheromones.
The lepidopteran order of insects includes large families of butterflies and moths whose larvae can devastate critical and valuable crops. Two pheromone-based pest control methods are used primarily, mass trapping and mating disruption. With the former method, female sex pheromones are placed in a trap that attracts and kills male insects. Mating disruption involves dispersing pheromones over a large area, effectively overloading the sensory organs of male insects and preventing them from being able to locate females that are releasing a much smaller amount of the same pheromones. This synergistic effect prevents mating and has been shown to reduce specific insect populations dramatically. Pheromones also play an essential role in integrated pest management (IPM), which involves monitoring insect populations and using appropriate, cost-effective pest control methods. The amount of insects captured in pheromone traps is correlated to the pest's population, which allows for a more targeted approach, reducing wasteful practices.
Pheromones of the lepidopteran order of insects are traditionally defined as straight chained hydrocarbon acetates, alcohols, or aldehydes containing 10 to 18 carbons and 1 to 3 double bonds with various olefin geometries. The presence of functional groups and alkenes makes ruthenium-based olefin metathesis an attractive methodology for the synthesis of these species. The synthesis of trans-olefin containing mono- and di-unsaturated pheromones utilizing olefin metathesis has been accomplished. The efficient synthesis of cis-containing pheromones has remained a challenge. Current synthesis of such species involves inefficient and costly processes, including the use of acetylene and poisoned hydrogenation catalysts.